1XRD

Light-Harvesting Complex 1 Alfa Subunit from Wild-Type Rhodospirillum rubrum

Summary for 1XRD

• Entry DOI: 10.2210/pdb1xrd/pdb
• Related: 1WRG
• NMR Information: BMRB: 6349
• Descriptor: Light-harvesting protein B-880, alpha chain (1 entity in total)
• Functional Keywords: membrane spanning helix, light-harvesting, pigment binding, photosynthesis, membrane protein
• Biological source: Rhodospirillum rubrum
• Cellular location: Cell inner membrane; Single-pass type II membrane protein: P02947
• Total number of polymer chains: 1
• Total formula weight: 6081.16

Authors

Wang, Z.-Y.,Gokan, K.,Kobayashi, M.,Nozawa, T. (deposition date: 2004-10-14, release date: 2005-03-15, Last modification date: 2024-05-29)

Primary citation

Wang, Z.-Y.,Gokan, K.,Kobayashi, M.,Nozawa, T.
Solution Structures of the Core Light-harvesting alpha and beta Polypeptides from Rhodospirillum rubrum: Implications for the Pigment-Protein and Protein-Protein Interactions
J.Mol.Biol., 347:465-477, 2005

PubMed Abstract: We have determined the solution structures of the core light-harvesting (LH1) alpha and beta-polypeptides from wild-type purple photosynthetic bacterium Rhodospirillum rubrum using multidimensional NMR spectroscopy. The two polypeptides form stable alpha helices in organic solution. The structure of alpha-polypeptide consists of a long helix of 32 amino acid residues over the central transmembrane domain and a short helical segment at the N terminus that is followed by a three-residue loop. Pigment-coordinating histidine residue (His29) in the alpha-polypeptide is located near the middle of the central helix. The structure of beta-polypeptide shows a single helix of 32 amino acid residues in the membrane-spanning region with the pigment-coordinating histidine residue (His38) at a position close to the C-terminal end of the helix. Strong hydrogen bonds have been identified for the backbone amide protons over the central helical regions, indicating a rigid property of the two polypeptides. The overall structures of the R.rubrum LH1 alpha and beta-polypeptides are different from those previously reported for the LH1 beta-polypeptide of Rhodobacter sphaeroides, but are very similar to the structures of the corresponding LH2 alpha and beta-polypeptides determined by X-ray crystallography. A model constructed for the structural subunit (B820) of LH1 complex using the solution structures reveals several important features on the interactions between the LH1 alpha and beta-polypeptides. The significance of the N-terminal regions of the two polypeptides for stabilizing both B820 and LH1 complexes, as clarified by many experiments, may be attributed to the interactions between the short N-terminal helix (Trp2-Gln6) of alpha-polypeptide and a GxxxG motif in the beta-polypeptide.

PubMed: 15740753
DOI: 10.1016/j.jmb.2005.01.017

Experimental method

SOLUTION NMR